The use of balloon expandable metallic intracoronary stents is gaining acceptance as a potential future adjunct to standard angioplasty to 1) prevent abrupt closure, 2) improve acute angioplasty results, and 3) prevent chronic restenosis. However, in a small (5-10%) number of patients immediately after stent implantation, subacute thrombotic closure results in important adverse clinical consequences. Therefore, an understanding of the clinical spectrum and predicted factors of subacute thrombotic events after coronary stent placement would be extremely important. We retrospectively analyzed operational, equipment, pharmacologic, and other treatment variables which might contribute to subacute thrombotic events after stent implantation. The clinical spectrum of subacute thrombotic events includes early onset (range 2-11 days) of acute chest pain with ECG evidence of evolving acute transmural infarction resulting in total closure of the stent treatment site requiring a combination of local thrombolysis and mechanical recanalization using guidewire and balloon techniques. The majority of patients develop either Q-wave or non Q-wave infarctions, but there have been no deaths thus far in the 157 patients analyzed, including 12 subacute thrombotic events. Predicted factors for thrombotic closure included a higher platelet count, small stent size, multiple stent placements, angiographic evidence of thrombus formation immediately before or after stent placement, and the -absence of systemic anticoagulation with coumadin. We believe that further critical analysis of this data set will help to define a variety of situational and treatment variables which will importantly reduce the frequency of thrombotic events after stent implantation in the coronary arteries.